Bakgrund På grund av den enorma konsumtion av textilier och kläder som sker i vissa delar av världen krävs ett förändrat förhållningssätt till hur de textilier och kläder som köps hanteras både under och efter användande. En stor påverkan har även de företag som designar, tillverkar och säljer produkterna. För att minska användandet av ändliga resurser krävs en strategi som förändrar dagens linjära flöden till ett slutet kretslopp där resurser används på nytt, om och om igen, en så kallad Closed-loop supply chain. Studiens syfte är att undersöka hur fyra svenska detaljhandelsföretag inom modebranschen arbetar med just Closed-loop supply chain och dess möjligheter och utmaningar med konceptet. Syftet är även att se hur företagen arbetar med återvinning och hållbarhet som är relevanta delar i ett fungerande cirkulärt flöde. Genomförande Den teoretiska referensramen beskriver konceptet Closed-loop supply chain och de delar som innefattas, framåtriktad och omvänd försörjningskedja. Den tar även upp sju processteg som måste hanteras för att skapa en Closed-loop supply chain för kläder och textilier. För att undersöka hur de fyra svenska detaljhandelsföretagen inom modebranschen arbetar för att uppnå ett cirkulärt flöde har en grundlig genomgång av respektive företags hållbarhetsrapporter gjorts. I empiriavsnittet presenteras förutom de fyra svenska detaljhandelsföretagen även ett antal organisationer som på något vis arbetar för att möjliggöra ett cirkulärt flöde inom textil- och modebranschen. För att få en bild av konsumenternas kännedom och attityd till återvinningsmöjligheter genomfördes även en enkätundersökning. Resultat För att skapa rätt förutsättningar för att skapa en Closed-loop supply chain krävs det att både den framåtriktade och den omvända försörjningskedjan är anpassad till det. Den framåtriktade försörjningskedjan kräver att klädesplaggen är designade för att enkelt kunna återvinnas och att de av konsumenten är hanterade på ett så hållbart sätt som möjligt. Den omvända försörjningskedjan kräver först och främst att kläderna samlas in. Vidare krävs att de insamlade kläderna sedan skickas vidare för sortering och därefter ta ett beslut om ett lämpligt återanvändningsalternativ. Slutligen omdistribueras produkten för att antingen återföras in i något processteg i den framåtriktade försörjningskedjan eller säljas på en andrahandsmarknad. Av den information som framkommit ur hållbarhetsrapporter och övrig informationsinsamling har det kunnat konstaterats att detaljhandelsföretagen har en lång väg att gå till dess att en Closed-loop supply chain fungerar till 100 %. / Background Due to the enormous consumption of textiles and clothing that takes place in some parts of the world, a changed approach is needed to handle the textiles and clothing that are purchased both during and after use. The companies that design, manufacture and sell the products also have a big impact. In order to reduce the use of finite resources, a strategy that changes today's linear flows into a closed cycle, where resources are recycled, a so-called Closed-loop supply chain, is required. The purpose of the study is to investigate how four Swedish retailers in the fashion industry work with Closed-loop supply chain and the possibilities and challenges with the concept. The purpose is also to find out how companies work with recycling and sustainability that are relevant parts of a functioning circular flow Implementation The theoretical reference framework describes the Closed-loop supply chain concept and the components that are included; forward and reverse supply chain. It also takes up seven process steps that must be handled to create a Closed-loop supply chain for clothes and textiles.To investigate how the four Swedish retail companies in the fashion industry work to achieve a circular flow, a profound review of the respective company's sustainability reports has been made. In the empirical section, apart from the four Swedish retail companies, there are also a number of organizations that in one way or another work to allow circular flow in the textile and fashion industry. In order to get a reflection of consumers' awareness and attitude towards recycling opportunities, a survey was also conducted. Results In order to create the right conditions for a Closed-loop supply chain, it is necessary to adapt both the forward and the reverse supply chain. The forward supply chain requires that the garments are designed to be easily recycled and that they are handled by the consumer in a sustainable way. The reverse supply chain primarily requires that the clothes are collected. Furthermore, the collected clothes are forwarded for sorting and then a decision of the garments reuse options has to be taken. Finally, the product is redistributed either back into any process in the forward supply chain or sold in a secondary market. From the information obtained from the sustainability reports and other information gathering, it has been found that retail companies have a long way to go until a Closed-loop supply chain operates to 100%.

Les systèmes d’imagerie médicale ultrasonore ont considérablement amélioré le diagnostic clinique par une meilleure qualité des images grâce à des systèmes plus sensibles et des post-traitements. La communauté scientifique de l’imagerie ultrasonore a consenti à un très grand effort de recherche sur les posttraitements et sur le codage de l’excitation sans s’intéresser, outre mesure, aux méthodes de commandeoptimale. Ce travail s’est donc légitimement tourné vers les méthodes optimales basées sur l’utilisationd’une rétroaction de la sortie sur l’entrée. Pour rendre applicable ces méthodes, ce problème complexe decommande optimale a été transformé en un problème d’optimisation paramétrique sous-optimal et plussimple. Nous avons appliqué ce principe au domaine de l’imagerie ultrasonore : l’échographie, l’imagerieharmonique native et l’imagerie harmonique de contraste avec ou sans codage de la commande.La simplicité de l’approche nous a permis, par une modification de la fonction de coût, de l’adapter àl’imagerie harmonique. Cette adaptation montre que la méthode peut être appliquée à l’imagerie ultrasonoreen générale. / Medical ultrasound imaging systems have greatly improved the clinical diagnosis by improvingthe image quality thanks to more sensitive systems and post-processings. The scientific community has madea great effort of research on post-processing and on encoding the excitation. The methods of the optimalcontrol have been neglected. Our work has focused on the optimal methods based on the feedback fromoutput to input. We have transformed the complex problem of optimal control into an easier suboptimalparametric problem. We apply the principle of optimal control to the ultrasound imaging, the ultrasoundharmonic imaging and to the constrast harmonic imaging with or without encoding.The simplicity of the method has allowed us to adapt it to harmonic imaging by a change in the costfunction. This adaptation shows that our method can usually be applied to the ultrasound imaging.

Type 1 diabetes in pregnancy is associated with higher rates of maternal and infant complications. The complications are associated with maternal hyperglycaemia. Thus, the main goal of treatment for these women is to optimise glycaemic control and thereby improve clinical outcomes for themselves and for their baby. This thesis examines glycaemic control in the mothers and infants of pregnancies affected by type 1 diabetes. I present the first home studies of closed-loop insulin delivery in this population. The aim of these studies was to assess the feasibility, efficacy, and utility of overnight and then day-and-night closed-loop insulin delivery in pregnant women with type 1 diabetes. The overnight study, which examined 16 pregnant women (mean age 34.1 years, HbA1c 6.8%, 14.4 weeks gestation), compared overnight use of the closed-loop system with sensor-augmented pump therapy in a 2x4-week randomised crossover design. We found that closed-loop therapy was associated with a 15% improvement in overnight time spent with target glucose concentration (3.5-7.8 mmol/L; 74.7% during closed-loop use vs 59.5% during sensor-augmented pump therapy use). The day-and night study also examined 16 pregnant women (mean age 32.8 years, HbA1c 8.0%, 16.4 weeks’ gestation) using a 2x4-week randomised crossover design to compare continuous day-and-night use of closed-loop insulin delivery with sensor-augmented pump therapy. This study enrolled a more diverse range of participants than the overnight study, but found that closed-loop therapy was associated with comparable glucose control and significantly less hypoglycaemia than sensor-augmented pump therapy. Chapter 4 examines women’s experiences of using the closed-loop system during pregnancy. While the system was generally well-received by participants, individual interactions and perceptions of the system varied markedly, and often did not align with biomedical measures of glycaemic response. After participation in either crossover study, participants could choose to continue using the technology until delivery (overnight study), or until 6 weeks post-partum (day and night study). Those data are presented in Chapters 2 and 3. The combined data from the women who used the closed-loop system during labour and delivery in either study are presented in Chapter 5. Tight glycaemic control during labour and delivery has traditionally been considered important for reducing rates of neonatal hypoglycaemia. However, despite very tight maternal glycaemic control in the women who used closed-loop insulin delivery, rates of neonatal hypoglycaemia were high. In order to better characterise the relationship between maternal glucose control in type 1 diabetes pregnancy and neonatal hypoglycaemia, Chapter 6 details an observational study in which continuous glucose monitoring was used to measure maternal and neonatal glycaemic control in 16 mother-infant pairs. The study found that, while neonatal hypoglycaemia was very frequent, it was generally, but not always, detected and treated effectively. Together, these studies suggest that a novel management tool, closed-loop insulin delivery, can improve overnight glycaemic control, and perhaps reduce hypoglycaemia during type 1 diabetes-affected pregnancies above what is possible with currently available treatments. However, complication rates remain high for these women and their babies. Further research is needed both to further develop treatments that can improve maternal glycaemic control, and to better understand the pathogenesis of diabetes-related pregnancy complications, with the ultimate goal of improving outcomes for women and their children. A definitive trial to assess the clinical efficacy, patient acceptability, and cost effectiveness of closed-loop is now warranted.

Achieving tight glucose control safely in type 1 diabetes with currently available methods of insulin delivery is challenging. Aggressive regimens carry an increased risk of hypoglycaemia, particularly overnight. Both alcohol consumption and exercise predispose further to low glucose levels. The demands are even greater in pregnancy where, in addition to limiting hypoglycaemia, avoidance of postprandial hyperglycaemia is critical to minimising adverse obstetric outcomes. The aim of my studies was to evaluate feasibility and safety of a closed-loop or ’artificial pancreas’ system linking insulin delivery with continuous glucose monitoring (CGM), in adults with type 1 diabetes in a controlled setting. Three randomised crossover studies compared closed-loop insulin delivery with conventional insulin pump therapy on two separate occasions, matched in meals and activities. During closed-loop visits, CGM values were entered into a computer containing a model predictive control algorithm which advised on basal insulin infusion for subcutaneous delivery, every 15 minutes. During control visits, usual insulin pump regimen was continued. The feasibility study evaluated overnight closed-loop in 12 adults (seven females, mean age 37.7 years, HbA1c 7.8%) following 60g- carbohydrate evening meal. A follow-up study assessed overnight closed-loop in 12 further adults (seven females, mean age 37.2 years, HbA1c 7.8%) following 100g-carbohydrate meal and (mean 564 ml) white wine. The third study evaluated 24 hours of closed-loop in 12 pregnant women (mean age 32.9 years, 19 to 23 weeks gestation, HbA1c 6.4%) during normal daily activities, including low and moderate intensity exercise. Activity and glucose levels were also measured during free-living. CGM performance during exercise was evaluated. Overnight closed-loop insulin delivery in adults, compared with conventional pump therapy, increased time spent with plasma glucose in target range (3.9−8.0 mmol/l) following both standard meal (81% versus 57%; p = 0.012) and large meal accompanied by alcohol (70% versus 46%; p = 0.012). Glycaemic variability, and time spent in hypo- and hyper- glycaemia were lowered. In pregnant women, day and night closed-loop insulin delivery was as effective as usual pump regimen (81% versus 81% time spent with plasma glucose 3.5−7.8 mmol/l; p = 0.754). Hypoglycaemia occurred following exercise, although closed-loop prevented nocturnal episodes. Glycaemic control during free-living was suboptimal, compared with controlled diet and exercise conditions. Accuracy of CGM was lower during exercise. In conclusion, these studies confirm the feasibility and efficacy of overnight closed-loop insulin delivery in adults with type 1 diabetes. Closed-loop is safe during pregnancy and may be beneficial in women with suboptimal glycaemic control. Meals and physical activity currently limit optimal daytime use of closed-loop.

abstract: Advances in implantable MEMS technology has made possible adaptive micro-robotic implants that can track and record from single neurons in the brain. Development of autonomous neural interfaces opens up exciting possibilities of micro-robots performing standard electrophysiological techniques that would previously take researchers several hundred hours to train and achieve the desired skill level. It would result in more reliable and adaptive neural interfaces that could record optimal neural activity 24/7 with high fidelity signals, high yield and increased throughput. The main contribution here is validating adaptive strategies to overcome challenges in autonomous navigation of microelectrodes inside the brain. The following issues pose significant challenges as brain tissue is both functionally and structurally dynamic: a) time varying mechanical properties of the brain tissue-microelectrode interface due to the hyperelastic, viscoelastic nature of brain tissue b) non-stationarities in the neural signal caused by mechanical and physiological events in the interface and c) the lack of visual feedback of microelectrode position in brain tissue. A closed loop control algorithm is proposed here for autonomous navigation of microelectrodes in brain tissue while optimizing the signal-to-noise ratio of multi-unit neural recordings. The algorithm incorporates a quantitative understanding of constitutive mechanical properties of soft viscoelastic tissue like the brain and is guided by models that predict stresses developed in brain tissue during movement of the microelectrode. An optimal movement strategy is developed that achieves precise positioning of microelectrodes in the brain by minimizing the stresses developed in the surrounding tissue during navigation and maximizing the speed of movement. Results of testing the closed-loop control paradigm in short-term rodent experiments validated that it was possible to achieve a consistently high quality SNR throughout the duration of the experiment. At the systems level, new generation of MEMS actuators for movable microelectrode array are characterized and the MEMS device operation parameters are optimized for improved performance and reliability. Further, recommendations for packaging to minimize the form factor of the implant; design of device mounting and implantation techniques of MEMS microelectrode array to enhance the longevity of the implant are also included in a top-down approach to achieve a reliable brain interface. / Dissertation/Thesis / Ph.D. Bioengineering 2013

No description available.

Den globala uppvärmningen anses idag vara ett av de största hoten mot vår planet. Vi människor är en stor bidragande orsak, efter årtionden av ständigt ökande utsläpp och gränslös konsumtion. Åtgärder måste genomföras inom samtliga sektorer i vårt samhälle. En av dessa sektorer är textilindustrin som årligen producerar mängder med nya produkter för att täcka kunders behov av ständig förnyelse. Som ett steg bort från det linjära slit-och-släng-samhället har företag börjat implementera cirkulära försörjningskedjor, s.k. closed-loop supply chains (CLSC). Denna studie undersöker hur svenska detaljhandelsföretag inom modebranschen arbetar med CLSC för att minska sin klimatpåverkan men även för att skaffa sig konkurrensfördelar. Detta görs genom en teorigenomgång som ligger till grund för en empirisk studie av fyra företag, där två av företagen studeras djupgående genom intervjuer med representanter från företagen. De två andra företagen har studerats på grundare nivå genom granskning av företagens hållbarhetsredovisning och hemsidor. Författarna undersöker även vilka drivkrafter och hot som företag ser med CLSC.

Closed-loop optimization deals with problems in which candidate solutions are evaluated by conducting experiments, e.g. physical or biochemical experiments. Although this form of optimization is becoming more popular across the sciences, it may be subject to rather unexplored resourcing issues, as any experiment may require resources in order to be conducted. In this thesis we are concerned with understanding how evolutionary search is affected by three particular resourcing issues -- ephemeral resource constraints (ERCs), changes of variables, and lethal environments -- and the development of search strategies to combat these issues. The thesis makes three broad contributions. First, we motivate and formally define the resourcing issues considered. Here, concrete examples in a range of applications are given. Secondly, we theoretically and empirically investigate the effect of the resourcing issues considered on evolutionary search. This investigation reveals that resourcing issues affect optimization in general, and that clear patterns emerge relating specific properties of the different resourcing issues to performance effects. Thirdly, we develop and analyze various search strategies augmented on an evolutionary algorithm (EA) for coping with resourcing issues. To cope specifically with ERCs, we develop several static constraint-handling strategies, and investigate the application of reinforcement learning techniques to learn when to switch between these static strategies during an optimization process. We also develop several online resource-purchasing strategies to cope with ERCs that leave the arrangement of resources to the hands of the optimizer. For problems subject to changes of variables relating to the resources, we find that knowing which variables are changed provides an optimizer with valuable information, which we exploit using a novel dynamic strategy. Finally, for lethal environments, where visiting parts of the search space can cause the permanent loss of resources, we observe that a standard EA's population may be reduced in size rapidly, complicating the search for innovative solutions. To cope with such scenarios, we consider some non-standard EA setups that are able to innovate genetically whilst simultaneously mitigating risks to the evolving population.

Closed-loop system identification and validation are important components in dynamic system modelling. In this dissertation, a comprehensive literature survey is compiled on system identification with a specific focus on closed-loop system identification and issues of identification experiment design and model validation. This is followed by simulated experiments on known linear and non-linear systems and experiments on a pilot scale distillation column. The aim of these experiments is to study several sensitivities between identification experiment variables and the consequent accuracy of identified models and discrimination capacity of validation sets given open and closed-loop conditions. The identified model structure was limited to an ARX structure and the parameter estimation method to the prediction error method. The identification and validation experiments provided the following findings regarding the effects of different feedback conditions: <ul> <li>Models obtained from open-loop experiments produced the most accurate responses when approximating the linear system. When approximating the non-linear system, models obtained from closed-loop experiments were found to produce the most accurate responses.</li> <li>Validation sets obtained from open-loop experiments were found to be most effective in discriminating between models approximating the linear system while the same may be said of validation sets obtained from closed-loop experiments for the nonlinear system.</li> </ul> These finding were mostly attributed to the condition that open-loop experiments produce more informative data than closed-loop experiments given no constraints are imposed on system outputs. In the case that system output constraints are imposed, closed-loop experiments produce the more informative data of the two. In identifying the non-linear system and the distillation column it was established that defining a clear output range, and consequently a region of dynamics to be identified, is very important when identifying linear approximations of non-linear systems. Thus, since closed-loop experiments produce more informative data given output constraints, the closed-loop experiments were more effective on the non-liner systems. Assessment into other identification experiment variables revealed the following: <ul> <li>Pseudo-random binary signals were the most persistently exciting signals as they were most consistent in producing models with accurate responses.</li> <li>Dither signals with frequency characteristics based on the system’s dominant dynamics produced models with more accurate responses.</li> <li>Setpoint changes were found to be very important in maximising the generation of informative data for closed-loop experiments</li></ul> Studying the literature surveyed and the results obtained from the identification and validation experiments it is recommended that, when identifying linear models approximating a linear system and validating such models, open-loop experiments should be used to produce data for identification and cross-validation. When identifying linear approximations of a non-linear system, defining a clear output range and region of dynamics is essential and should be coupled with closed-loop experiments to generate data for identification and cross-validation. / Dissertation (MEng)--University of Pretoria, 2009. / Chemical Engineering / unrestricted

abstract: ABSTRACT Historically, Life Cycle Assessments (LCA) guided companies to make better decisions to improve the environmental impacts of their products. However, as new Circular Economy (CE) tools emerge, the usefulness of LCA in assessing linear products grow more and more obsolete. Research Question: How do LCA-based tools account for reuse/multiple life cycles of products verses CE-based tools? The Kaiteki Innovation Framework (KIF) was used to address the question of circularity of two packaging materials using an Environmental LCA to populate its 12 CE dimensions. Any gaps were evaluated with 2 LCA- based and 2 CE-based tools to see which could address the leftover CE dimensions. Results showed that to complete the KIF template, LCA data required one of the LCA-based tools: Social Life Cycle Assessment (SLCA) and both CE-based tools: Circular Transition Indicators (CTI) and Material Circularity Indicator (MCI) to supplement gaps in the KIF. The LCA addressed 5 of the KIF dimensions: Innovation Category Name, Description, GHG Impact, Other Environmental Impacts, and Value Chain Position. 3 analytical tools addressed 5 more:: Effect on Circularity, Social Impacts, Enabling Technologies, Tier 2 and 3 Requirements, and Value Chain Synergies. None of the tools could address the KIF Dimensions: State of Development or Scale Requirements. All in all, the KIF required both LCA-based and CE-based tools to cover social and socio-economic impacts from a cradle-to-cradle perspective with multiple circular loops in mind. These results can help in the research and development of innovative, circular products that can lead to a more environmentally preferred future. / Dissertation/Thesis / Masters Thesis Sustainability 2020